Conventionally, various technologies of improving the detection accuracy are proposed in a laser radar device, which projects a measurement light beam that is of a pulsed laser beam to a predetermined monitoring area to simultaneously receive reflected light in a plurality of directions using a plurality of light receiving elements.
For example, in one of the proposed technologies, the plurality of light receiving elements are selected with any combination, and light receiving signals output from the selected light receiving elements are output while added, thereby enhancing light sensitivity. It has been proposed that degradation of resolution in a horizontal direction due to the addition of the plurality of light receiving signals is constrained by switching the selection of the light receiving element every time the measurement light beam is projected (for example, see Japanese Unexamined Patent Publication No. 7-191148).
For example, in one of the proposed technologies, the light receiving signal used to detect an object is selected from the light receiving signals of the light receiving elements based on a steering angle, and the object is detected using the selected light receiving signal to reduce the scale of a circuit or arithmetic processing necessary to measure the light receiving value. It has been proposed that the light sensitivity is enhanced by integrating the light receiving signals of the identical light receiving element with respect to the plurality of measurement light beams (for example, see Japanese Unexamined Patent Publication No. 2012-242218).
For example, in one of the proposed technologies, the light receiving signal of each light receiving element is sampled at predetermined sampling time intervals, and sampling values of the light receiving signals of the identical light receiving element at each sampling clock time are integrated with respect to the plurality of measurement light beams, thereby enhancing the light sensitivity at each sampling clock time of each light receiving element (for example, see Japanese Unexamined Patent Publication No. 2013-33024).